755 ILCS 5/2-6
A person who intentionally and unjustifiably causes the death of another shall not receive any property, benefit, or other interest by reason of the death, whether as heir, legatee, beneficiary, joint tenant, survivor, appointee or in any other capacity and whether the property, benefit, or other interest passes pursuant to any form of title registration, testamentary or nontestamentary instrument, intestacy, renunciation, or any other circumstance. The property, benefit, or other interest shall pass as if the person causing the death died before the decedent, provided that with respect to joint tenancy property the interest possessed prior to the death by the person causing the death shall not be diminished by the application of this Section. A determination under this Section may be made by any court of competent jurisdiction separate and apart from any criminal proceeding arising from the death, provided that no such civil proceeding shall proceed to trial nor shall the person be required to submit to discovery in such civil proceeding until such time as any criminal proceeding has been finally determined by the trial court or, in the event no criminal charge has been brought, prior to one year after the date of death. A person convicted of first degree murder or second degree murder of the decedent is conclusively presumed to have caused the death intentionally and unjustifiably for purposes of this Section.
The holder of any property subject to the provisions of this Section shall not be liable for distributing or releasing said property to the person causing the death if such distribution or release occurs prior to a determination made under this Section.
If the holder of any property subject to the provisions of this Section knows or has reason to know that a potential beneficiary caused the death of a person within the scope of this Section, the holder shall fully cooperate with law enforcement authorities and judicial officers in connection with any investigation of such death.
755 ILCS 5/2-6